1. Field of the Invention
This invention generally relates to a method of transmitting data, and more particularly to a method of transmitting data which reduces electro-magnetic interference and power consumption.
2. Description of Related Art
Data transmission is generally performed by a transmitter and a receiver. When transmitting data, the transmitter sends the data to the receiver. For example, in a liquid crystal display (LCD), a transmitter and receiver pair may include the panel controller (i.e., the transmitter) and source driver (i.e., the receiver). The panel controller will send the data to the source driver and the source driver will receive the data from the panel controller.
FIG. 1 is a schematic view of a conventional data transmission scheme. Referring to FIG. 1, the transmitter 102 sends a plurality of data signals (Data Signal 1, Data Signal 2, . . . Data Signal N) to the receiver 104 and the receiver 104 will receive the data signals (Data Signal 1, Data Signal 2, . . . Data Signal N). Currently, most data signals are transistor-transistor logic (TTL) signals; the high level voltage of the TTL signals is about 3.5V; the low level voltage of the TTL signals is about0V. Hence, when transmitting the data signals (Data Signal 1, Data Signal 2, . . . Data Signal N), the data signals will suffer serious electro-magnetic interference (EMI) and require more power consumption, since EMI and power consumption are proportional to the voltage level of the data signals.
FIG. 2 is a schematic view of another conventional data transmission scheme. Compared to FIG. 1, the data transmission in FIG. 2 transmits differential data signals (Data Signal 1±, Data Signal 2±, . . . Data Signal N±) rather than the data signals (Data Signal 1, Data Signal 2, . . . Data Signal N) to reduce the EMI and power consumption. Because the voltage level of the differential data signals is lower than that of the data signals, the data transmission in FIG. 2 can reduce the EMI and power consumption.
Although the use of the differential data signals can reduce the EMI and power consumption, however when the transmission rate gets higher and a significant amount of differential data signals are in transition, the EMI and power consumption are still unacceptable. Therefore, when the transmission rate is getting higher, how to reduce the EMI and power consumption becomes an important issue.